If you drink a lot of seltzer, listen up. You may believe that bubbly water is a super-healthy alternative to soda. This is logical, because how could calorie-free, sugar-free, and sodium-free water with bubbles possibly be bad for you? But, tragically, it turns out that seltzer could actually be harmful your teeth if you drink enough of it.

Atlantic writer and fizzy water aficionado Olga Khazan, who once consumed twelve cans of La Croix sparkling water during one standard work day, had a random musing that turned into a nightmare.

Khazan spoke to Damien Walmsley, a professor of dentistry, who said there was a "theoretical risk" of tooth erosion if the drinks were consumed over a long period of time. He said: “My advice is to keep acidic drinks to meal times, and if you have to sip drinks between meals, then plain water is the safest.”

Luckily, this acid in plain seltzer is relatively weak, especially when compared to the acids in other drinks like orange juice or some colas. But when it comes to flavored seltzers, the situation can get a little hairy.

Researchers at the University of Birmingham tested the acidity of flavored soda waters, and the results were not good. The flavored seltzers they tested had high pH levels ranging from 2.74 to 3.34, showing them to be fairly acidic. For reference, stomach acid has a pH of 2, and battery acid has a pH of 1. Normal, un-carbonated water has a neutral pH of 7, compared to 2.4 for orange juice and 2.5 for some colas.

If seltzer is the only thing that brings joy to your life (and we won't judge) make sure to take great care of your teeth. Brush correctly, always floss, and make sure you're attending regular dental checkups.